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Title: Fractal dynamics of light scattering intensity fluctuation in disordered dusty plasmas

Dynamic light scattering (DLS) technique is a simple and yet powerful technique for characterizing particle properties and dynamics in complex liquids and gases, including dusty plasmas. Intensity fluctuation in DLS experiments often studied using correlation analysis with assumption that the fluctuation is statistically stationary. In this study, the temporal variation of the nonstationary intensity fluctuation is analyzed directly to show the existence of fractal characteristics by employing wavelet scalogram approach. Wavelet based scale decomposition approach is used to separate non-scaling background noise (without dust) from scaling intensity fluctuation from dusty plasma. The Hurst exponents for light intensity fluctuation in dusty plasma at different neutral gas pressures are determined. At low pressures, weaker damping of dust motions via collisions with neutral gases results in stronger persistent behavior in the fluctuation of DLS time series. The fractal scaling Hurst exponent is demonstrated to be useful for characterizing structural phases in complex disordered dusty plasma, especially when particle configuration or sizes are highly inhomogeneous which makes the standard pair-correlation function difficult to interpret. The results from fractal analysis are compared with alternative interpretation of disorder based on approximate entropy and particle transport using mean square displacement.
Authors:
; ; ; ; ;  [1]
  1. Plasma Technology Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)
Publication Date:
OSTI Identifier:
22218579
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; APPROXIMATIONS; BACKGROUND NOISE; COLLISIONAL PLASMA; COMPARATIVE EVALUATIONS; CORRELATION FUNCTIONS; CORRELATIONS; DAMPING; DUSTS; ENTROPY; FLUCTUATIONS; FRACTALS; LIGHT SCATTERING; LIGHT TRANSMISSION; PLASMA DIAGNOSTICS; VISIBLE RADIATION